[Tex/LaTex] Problems with alignment of sequences

alignarrayshorizontal alignment

I want to align two sequences:

a_1, b_1, c_1, d_1, e_1 etc.

a_2, b_2, c_2, d_2, e_2 etc.

here's what I wrote

    \begin{align}
    \notag &a_1,\ &b_1,\ &c_1,\ &d_1,\ &e_1\ \mbox{etc.}\\
    \notag &a_2,\ &b_2,\ &c_2,\ &d_2,\ &e_2\ \mbox{etc.}
    \end{align}

but it turns out that the first two columns are perfect, but then there is a large space between the second and third column. How can I solve this? Any help is appreciated.

Best Answer

Your alignment is perhaps better obtained using a structure like array:

enter image description here

\documentclass{article}
\usepackage{amsmath}% http://ctan.org/pkg/amsmath
\begin{document}
\begin{align*}
  &a_1,\ &b_1,\ &c_1,\ &d_1,\ &e_1\ \text{etc.}\\
  &a_2,\ &b_2,\ &c_2,\ &d_2,\ &e_2\ \text{etc.}
\end{align*}

\[
  \begin{array}{*{6}{l@{\ }}}
    a_1, & b_1, & c_1, & d_1, & e_1 & \text{etc.} \\[\jot]
    a_2, & b_2, & c_2, & d_2, & e_2 & \text{etc.}
  \end{array}
\]
\end{document}

The array consists of 6 l@{\ } columns - left-aligned, followed by a control-space \. \\[\jot] ensures a sizeable gap between the series, similar to that of align, while \text (provided by amsmath) does some testing to maintain the font size and is therefore superior to an \mbox construct (in general). In this case, it doesn't matter though.

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